Screw-driver



J. SONTHEIMER.

scnsw 11mm.

APPLICATION FILED SPT. 10. 1918.

1,325,383. Patented Deb. 16,1919.

INVENTO/i Jim Sonfheim'er ATTORNEYS UNITED sra'rns rarnn'r QTEFIQEF.

JOHN SONTHEIMER, OF LINCOLN, NEBRASKA.

SCREW-DRIVER.

To all whom it may concern:

Be it known that 1, JOHN SoN'ri-rnnrER, a citizen of the United States, and a resident of Lincoln, in the county of Lancaster and State of Nebraska, have invented a new and Improved Screw-Driver, of which the following is a full, clear, and exact description.

My invention relates to screw drivers and more especially to a screw driver involving an insertible blade.

Objects of the invention are to provide a relation between the blade and holder as to so position the front of the blade that the front end of the holder will bear against the screw in the operation of the tool, whereby to minimize the possibility of the screw dr1ver slipping from the screw; to provide a blade of a form that will further contribute to preventing the tool from slipping from the screw; and to provide a blade that may be reversed in the holder, thereby providing or adapting the tool to screws of various sizes.

Further important objects of the invention are to provide for the ready adjustment of the blade; and to provide for bracing the slotted holder against the separating strain exerted by the blade when the tool is in operation.

The invention also has for objects to provide spring means, whereby the blade will normally be projected a Suflicient distance beyond the holder to facilitate the engage? ment with the screw and to yield so that only a sufficient portion of the blade will project beyond the holder for entrance in the slot of the screw; and to provide a yielding guard adapted to inclose the screw both in driving a screw or removing it, the guard being an additional means to prevent the slipping of the tool from the screw.

Reference is tobe had to the accompanying drawings forming a part of this specification, it being understood that the drawings are merely illustrative of practical eramples of the invention.

Figure l is a longitudinal vertical section of a screw driver embodying my invention, showing the-same in operation and with the blade pressed back in the holder;

Fig. 2 is a side elevation at right angles to Fig. 1 and with the blade projected as in the normal position before the screw is engaged;

Fig. 3 is a cross section on the line 33,

Specification of Letters Patent. Patented Dem'lfi, 1919,

Application filed September 10, 1918. Serial No. 253,444.

0 Fig. 2, the spring of the guard being omitted;

Fig. f is an edge view of the reversible blade;

Fig. 5 is a view similar to Fig. 2, but showing a construction in which springs are not employed.

Referring more particularl to Figs. 1 to 4, the holder 10 is longitu inally slotted from the front end rearwardly as at 11 to receive the blade 12. Said blade has lateral lugs 13 at opposite edges which are engaged by means on the holder to limit rearward movement of the bladerin the holder and to adjust t e blade forwardly as it is worn away. In Figs. 1 and 2 the lugs 18 are in front of a sleeve 14: against which abuts the front end of aepring 15 coiled about the holder, the rear end of said spring abutting against. a compression nut 16 engaging threads 17 on the holder to vary the tension of the spring.

A tubular guard 18 is fitted on the holder 10 at the front end to be slidable thereon and has a front flange 19 against which bears the front end of a spring 20" coiled about the guard, the rear end of the said spring abutting against a compression nut 21 engaging threads 22 on the holder to regulate the projection of the guard beyond the holder. Said guard 18 has rearwardly extending arms 23slidable in slots 24 in the 20 to yield. With the described construction, the spring 15 will normally project the blade'l2 as in Fig. 2, to readily enter the slot'of the screw A. When engaged with the screwthe pressure exerted forwardly on the holder will cause the blade 12to renut 21 to permit the guard 18 and spring cede, the spring 15. yielding tothe pressure exerted on the sleeveor collar 14 by the result also, the blade 12 as clearly shown in Fig. 4, tapers from the front edge, this formation being the reverse of a tapered end, contributing also to the prevention of slipping since the blade will not have so great a tendency to cam ofi, so to speak, from the screw. It is to be noted that the blade in Fig. 4. is double-ended, so that it may be reversed and the ends will be of different size so that within the range of the capacity of the tool screws of practically every size can be properly engaged.

Obviously, the blade may be readily reversed to present either end forward. Also, the nuts 16, 21 provide for an adjustment of the parts to accommodate the blade as it is worn or ground away. With the screw engaged and pressed backward as in Fig. 1, as the screw is driven, the front end of the flange 19 of the guard 18 will come to a bearing against the surface 13 of the structure into which the screw is being driven and as the screw is finally driven home, the spring 18 will yield, permitting the guard to recede. The nut 21 has the important function also of bracing the slotted forward end of the holder to resist a scparating tendency of the blade when in operation.

In the form shown in Fig. 5 the holder 1O has a longitudinal slot 11 to receive a blade 12 which is the same form as first described. The holder is threaded externally at its forward end as at to receive nuts 16, 21*, the former receiving the thrust of the lugs 13 of the blade and the front nut 21 serving to brace the slotted holder to resist the separating strain exerted by the blade. The nut 16 determines the extent of projcction of the front end of the blade beyond the front end of the holder.

The rear end 25 of the holder is formed to be received in a bit brace for turning the tool and with my improved construction the only force required to actuate the screw after engagement with the blade is the turning force exerted to revolve the tool since no material forward pressure is required to maintain the engagement of the tool with the screw.

I would state in conclusion that while the illustrated examples constitute practical embodiments of my invention, I do not limit myself strictly to the mechanical details herein illustrated, since manifestly the same can be considerably varied without departure from the spirit of the invention, as defined in the appended claims.

Having thus described my invention, claim as new, and desire to secure by Letters Patent:

1. A screw driver including a holder hav: ing a longitudinal slot therein extending through the front end of the holder and the latter having external threads at said front end, adjustable means to limit the rearward movement of the blade in the holder, and a nut to engage said threads to brace the slotted portion of the holder against the separating strain of the blade when the tool is in use.

2. A screw driver including a holder, a separate blade adjustable in the holder, and means to dispose the blade in working position projecting from the holder to an extent that the front end of the holder will bear against the head of the crew when the projecting end of the blade is in the slot of the screw.

3. A screw driver including a holder having a slot extending through the front end thereof, a separate blade fitting said slot, lateral lugs on the blade projecting beyond said slot, and adjustable means on the holder rearward of said lugs and adapted to be en gaged by the latter to take the thrust of the blade.

l. A screw driver including a holder having a longitudinal slot extending through the front end thereof, a separate blade in said slot and spring-pressed means on the holder at the exterior and engageable by the blade to yieldingly take the thrust of the latter.

5. A screw driver having external threads thereon near the front end, a guard emracing the screw driver at said front end and projecting therebeyond, a coil spring abutting at its front end against said guard, a nut engaging said threads againstwhich nut the rear end of said spring abuts, and rearwardly extending arms on said guard, said nut having slots through which said arms may have sliding movement in response to the yielding of the guard and 81311110.

6. A screw driver including a holder having a slot extending through the front end thereof, said holder having external threads at said front end, a blade fitting said slot and having lugs projecting laterally beyond the sides of the slot, a nut engaging said threads rearward of said lugs and adapted to be engaged by the latter, and a second nut engaging said threads near the front end of the holder to brace the holder against the strain of the blade when in use.

JOHN SONTHEIMER.

VYitness:

D. WV. MOSELEY. 

